Lecture 9
Section B (Week 2): Environmental and Chemical Triggers of Immune System
Function and Dysfunction
6. How does the environment affect our immune system function?
7. Effects of Diet on the immune system?
8. What can we do to boost the function of our immune system – clinically proven
and homeopathic approaches?
9. Plagues, epidemics, pandemics – how have these events influenced our
knowledge of the immune system? Examples will be the Black Plague, Cholera,
Leprosy, Spanish Flu, H1N1, SARS
10. Treating immune disorders - the joys and pitfalls of the Pharmaceutical
Industry.
Definitions
The word pandemic comes from the Greek pandemos meaning
"pertaining to all people." The Greek word pan means "all" and the
Greek word demos means "people."
A pandemic is an outbreak of global proportions. It happens when
a novel virus emerges among humans - it causes serious illness
and is easily human transmissible (spreads easily from person-toperson).
A pandemic is usually caused by a new virus strain or subtype - a
virus humans either have no immunity against, or very little
immunity.
An epidemic is when the number of people who become infected
rises well beyond what is expected within a country or a part of a
country. When the infection takes place in several countries at the
same time it then starts turning into a pandemic.
Timeline of Discoveries
http://wowlit.org/blog/2013/09/02/catching-a-bug-reading-aboutpandemics-epidemics-and-outbreaks/
Timeline of Discoveries
https://prezi.com/vxxduftpb5hx/pandemicsand-the-globalizing-world/
THE FLU
How do influenza pandemics emerge?
A pandemic can emerge when the influenza A virus changes suddenly - what
experts call an antigenic shift. The HA and/or NA proteins, which are on the
surface of the virus, have new combinations; resulting in a new influenza A virus
subtype.
This new influenza subtype needs one characteristic to cause a pandemic - it
must be easily human transmissible (it can easily spread from one person to
another).
After the pandemic has emerged and spread, the virus subtype circulates among
humans for several years, causing occasional flu epidemics. These will not
usually become more than epidemics because humans have developed some
immunity over time. Various bodies around the world, such as the Health
Protection Agency (UK), the World Health Organization (WHO), and the Centers
for Disease Control and Prevention (CDC) monitor the behavior and movements
of the virus.
http://www.medicalnewstoday.com/articles/148945.php
Can we rid ourselves of pandemics?
Although medical science is constantly making leaps and bounds in our
defense against disease, because of the novel nature of pandemics, we
will never be fully protected.
Wild aquatic birds are a natural host for a variety of influenza strains. In
rare cases these influenza species can pass from bird to human, sparking
epidemics with the potential to turn into pandemics, if left unchecked.
The recent discovery of the H5N1 (Avian Flu) is an example of this. The
strain was spotted in Vietnam in 2004 and, although it never reached
even epidemic levels, the ability of the virus to potentially combine with
human flu viruses is a concern to scientists.
Swine FLU (H1N1)
Swine influenza, also called pig influenza, swine flu, hog flu and pig flu, is an
infection caused by any one of several types of swine influenza viruses.
As of 2009, the known SIV strains include influenza C and the subtypes
of influenza A known asH1N1, H1N2, H2N1, H3N1, H3N2, and H2N3.
Swine influenza virus is common throughout pig populations worldwide.
Transmission of the virus from pigs to humans is not common and does not
always lead to human flu, often resulting only in the production of antibodies in the
blood. If transmission does cause human flu, it is called zoonotic swine flu. People
with regular exposure to pigs are at increased risk of swine flu infection.
Around the mid-20th century, identification of influenza subtypes became
possible, allowing accurate diagnosis of transmission to humans. Symptoms of
zoonotic swine flu in humans include chills,fever, sore throat, muscle pains,
severe headache, coughing, weakness and general discomfort.
EBOLA
In 1976, Ebola (named after the Ebola River in Zaire) first emerged in Sudan and
Zaire
The first outbreak of Ebola (Ebola-Sudan) infected over 284 people, with a
mortality rate of 53% but the causative agent was never identified.
The third strain of Ebola, Ebola Reston (EBOR), was first identified in 1989 when
infected monkeys were imported into Reston, Virginia, from Mindanao in the
Philippines.
Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a
severe, often fatal illness in humans.
The virus is transmitted to people from wild animals and spreads in the human
population through human-to-human transmission with a fatality rate of 50%
There are currently no licensed Ebola vaccines but 2 potential candidates are
undergoing evaluation.
Images…
Influenza Virus (1000 000 X
magnification
Swine FLU (H1N1)
Virus
EBOLA Virus
EBOLA
The current outbreak in West Africa, (first cases notified in March 2014), is the largest
and most complex Ebola outbreak since the Ebola virus was first discovered in 1976.
Fruit bats of the Pteropodidae family are natural Ebola virus hosts. Ebola is
introduced into the human population through close contact with the blood,
secretions, organs or other bodily fluids of infected animals such as chimpanzees,
gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead
Ebola then spreads through human-to-human transmission via direct contact
(through broken skin or mucous membranes) with the blood, secretions, organs or
other bodily fluids of infected people, and with surfaces and materials (e.g. bedding,
clothing) contaminated with these fluids.
The incubation period, is 2 to 21 days. Humans are not infectious until they develop
symptoms. First symptoms are the sudden onset of fever fatigue, muscle pain,
headache and sore throat. This is followed by vomiting, diarrhoea, rash, symptoms of
impaired kidney and liver function, and in some cases, both internal and external
bleeding (e.g. oozing from the gums, blood in the stools). Laboratory findings include
low white blood cell and platelet counts and elevated liver enzymes.
HIV – an epidemic in Africa and for a
short time in North America
1982
HIV – an epidemic in Africa and for a
short time in North America
HIV – how did it happen?
Los Angeles, 1981
Two doctors in Los Angeles reported to the Centers for Disease Control in Atlanta that
they had discovered a rare kind of pneumonia caused by the bacteria, Pneumocystis
carinii, in five recent patients. All five were gay men. Two of them had unexpectedly died.
More stricken patients followed. Doctors in Los Angeles, San Francisco and New York
soon observed that something was destroying the immune systems of their gay patients.
And the number of cases quickly began to rise.
That summer researchers at the National Cancer Institute in Maryland used a new, stateof-the-art medical device called the Fluorescent Activated Cell Sorter to test the blood of
15 apparently healthy gay men from the Washington, D.C., area. The results were
disturbing - half the men had such severe abnormalities in their immune systems that the
lab technicians thought the machine had malfunctioned.
As the cases accumulated and hundreds of patients continued to die, researchers were
dumbfounded. They had no idea what they were dealing with. Was it a new venereal
disease? Did it only affect gays? Where had it come from? And what could they do to treat
their patients?
HIV – how did it happen?
THE VIRUS
Bethesda, Maryland, 1984
Researchers in Paris, San Francisco and at the National Cancer Institute in Bethesda,
Maryland, isolated the elusive human immunodeficiency virus, HIV, that was causing
AIDS.
Researchers soon learned that unlike quick-acting pathogens that cause smallpox, malaria
or the flu, HIV can lie in wait for a decade or more before overtaking its victim's immune
system and displaying its first symptoms.
For public health officials and epidemiologists, the isolation of the virus was a major
breakthrough, leading to tests for the presence of HIV antibodies in a patient's blood.
Armed with the new tests, researchers began to track the movement of the slow-acting
disease. By the first week of April 1984, more than 4,000 AIDS cases had been recorded
in the United States. And new case reports were coming in from around the world - 33
countries so far.
http://web.stanford.edu/class/stat30/web1/aids1.html
HIV – how did it happen?
University of California, Davis, 1985
Monkeys were mysteriously dying, too. For the past decade, Asian monkeys in research
centers across the United States had been dying from outbreaks of opportunistic
infections, and Preston Marx, a virologist at UC Davis, and other primate researchers
were baffled.
Then when the first AIDS cases in humans were reported, Marx and others began to
suspect that the monkeys were dying from a similar disease.
In 1985, researchers outside Boston isolated the virus that had been destroying the Asian
monkeys' immune systems. It bore intriguing genetic similarities to HIV, so they called it
SIV - simian immunodeficiency virus.
The primatologists finally traced the source of the virus to a species of medium-sized
monkeys called sooty mangabeys for the ash-gray color of their coats. The mangabeys,
which came from Africa, were often caged with the Asian monkeys. The odd thing was
that the mangabeys never got sick, even though they carried the virus and apparently
gave it to the Asian monkeys. Did they have an built up immunity?
HIV – how did it happen?
Sooty Mangabeys – in Coastal West Africa
HIV – how did it happen?
Edward Hooper published a book called
"The River" in which he contends the AIDS
epidemic was caused by a contaminated
polio vaccine that was given to hundreds of
thousands of people in Central Africa in the
1950s.
His theory, which some have called flawed,
cites the strong correlation between the rural
African clinics where the Wistar oral
vaccine was administered from 1957 to
1960 and the villages where the earliest
AIDS cases turned up
AIDS cases reported annually in the US
HIV Today…
http://www.rappler.com/moveph/ispeak/33044-hiv-aids-epidemic-action
HIV Today…
https://www.phan.ca/hiv-in-canada-putaribbononit/
Timeline of Discoveries
https://en.wikipedia.org/wiki/Vaccine
Disease Monitoring Organizations…
US - Center for Disease
Control (CDC), Atlanta
World Health Organization
Canada - Centers for Disease
Control and Prevention
Disease Monitoring Organizations…
Biosafety Level 1 - 4
What have we learnt from previous
pandemics/epidemics…
How to better track disease spread
How to efficiently and effectively to quarantine
patients to prevent progress to epidemic
How to rapidly identify new strains
How to inform the public about new outbreaks –
usefulness of social media
What can we do to protect ourselves
from pandemics/epidemics…
Pay attention to news reports about outbreaks
Avoid areas that actively have or have the
potential for outbreaks
Make sure your vaccinations are up to date to
promote a healthy immune system
Protect children and the elderly from contact with
outbreak areas